The research led to the obtainment of compositions of water-dilutable paints and lacquers as well as mineral plaster with the additive of nanofiller called Nanobent ® (bentonite modified with quaternary ammonium salt) which is a commercial product of ZGM Zębiec near Starachowice. The resistance of the abovementioned substances to mould fungi Aspergillus niger and Penicillium chrysogenum was tested. The best results were obtained for the composition with 3% additive of Nanobent ZR2 filler which practically completely inhibited the growth of mould fungi, even in the presence of whole culture medium containing glucose.